University College London researchers asked nearly 6,500 people, with an average age of 65 “How old do you feel you are?” 70 percent of the subjects felt younger, about a quarter felt their precise age and just under 5 percent felt a year or more older.

Those who felt older than they were had a higher death rate after a follow-up period of 99 months. Nearly a quarter of them passed away in that time. That compares with just 14 percent of those who felt younger and18.5 percent of those who felt their age.

The researchers suggest it could be that those who feel “young at heart” have healthier behaviors and more resilience, giving them a stronger will to live. The good news is, you can change your perception of how young you are, and your ideas about aging in general. Other studies show that can help you improve physical tasks like balancing, in addition to perhaps lengthening your life. So here’s some proof that age really is just a number.